This invention relates to anchoring devices for screw fasteners and particularly relates to plastic anchors which can be frictionally welded to the structure upon which the screw is mounted.
In the asembly or erection of structures in which fastening screws are mounted in a relatively thin sheet or panel of structural material, the screw shank is generally driven into an anchoring device which secures the shank and tightly engages the surface of the sheet or panel in order to prevent the screw from stripping out of the material during the screw installation or ripping out of the material when an applied load is imposed on the screw. Numerous types of discrete anchoring devices have been developed for applications in which the thin sheet material is not employed with a supporting material capable of securing the screw shank. However, the discrete anchoring devices have generally required manual alignment or attachment to the thin sheet material. For example, in fabricating the shell of a conventional home refrigerator, metal devices have typically been attached with adhesive to the plastic inner liner of the refrigerator shell in order to secure screws driven into the liner to support a shelf bracket within the refrigerator. The adhesive attachment of such anchoring devices has prevented entirely automatic fabrication of the refrigerator shell.